Trench boxes having side panels spaced apart with spreaders are used in trenches to hold out earth, mud, water and excavated debris so that work can proceed in the trench. The trench boxes are assembled at the work site. Lifting equipment is used to place the trench boxes into an earth opening. The trench boxes are pounded into the earth to a desired level by applying impact forces on top of the panels. These forces can damage the top members of the panels. Pounding rails having a tubular member filled with wood have been used as top members of the panels to help absorb impact during driving of the panels down to grade. The lower edge of each panel is beveled to facilitate penetration into the earth. An example of a trench panel having a beveled lower edge and a bar is disclosed by J. L. Griswold in U.S. Pat. No. 4,019,329. The trench box is moved along the trench as digging proceeds and the old opening behind the trench box is closed over the pipe or cable placed in the trench. The interior spaces between the side walls accommodate water impermeable low weight plastic foam to preclude the collection of mud and water in the panels. J. B. Cook in U.S. Pat. No. 4,259,028 discloses an example of a trench box panel having a foam plastic filler to prevent intrusion of water, mud and grime into the panel.